Fluid sample analysis system

ABSTRACT

A SYSTEM FOR ANALYZZING THE CONSTITUENTS OF LIQUID SAMPLE OF A TYPE WHEREIN BUFFERS OR OTHER SAMPLE CARRIER LIQUID ARE APPLIED TO THE SAMPLE CHARACTERIZED BY AN ION EXCHANGE COLUMN HAVING INPUT AND OUTPUT FLOW PASSAGES FOR PASSING THE SAMPLE AND BUFFERS THERETHROUGH TOGETHER WITH MEANS FOR SUPPLYING SAMPLE AND BUFFER TO THE INPUT FLOW PASSAGE OF THE COLUMN UNDER SUBSTANTIAL POSITIVE PRESSURE. THE COLUMN CONTAINS ION EXCHANGE MATERIAL FOR SEPARATING THE SAMPLE CONSTITUENTS ON A TIME BASIS. A REAGENT SUPPLY LINE UNDER SUBSTANTIAL POSITIVE PRESSURE DISCHARGES REAGENT INTO THE ELUENT OF THE ION EXCHANGE COLUMN FOR MIXING REAGENT AND ELUENT. FURTHER, MEANS IN THE REAGENT SUPPLY LINE PROVIDE A BACK PRESSURE RESISTANCE TO PASSAGE OF FLUID THERETHROUGH SUBSTANTIALLY MATCHED TO THE BACK PRESSURE RESISTANCE PROVIDED BY THE ION EXCHANGE COLUMN. THIS SYSTEM IS FURTHER CHARACTERIZED BY MEANS FOR MIXING THE EULENT AND REAGENT IN A MANNER WHICH SERVES TO INTERMINGLE REAGENT AND ELUENT BY LATERAL DEFLECTIONS OF THEIR TRAVEL ALONG THEIR FLOW PATHS WHILE INHIBITING AXIAL EXTENSION OF PORTIONS OF THE BODY OF MIXED MATEIAL TRAVELING ALONG THE FLOW PATH SO AS NOT TO UPSET THE TIMED RELATION OF THE DIFFERENT SUCCESSIVE CONSTITUENTS OF SAMPLE (SEPARATED OUT OF THE ION EXCHANGE COLUMN AT DIFFERENT TINES). IN ADDITION, THE SYSTEM IS FURTHER CHARACTERIZED BY A REACTION COIL IN THE FORM OF A LENGTH OF TUBING DISPOSED IN HEAT TRANSFER RELATION ABOUT A SUPPORT ELEMENT ADAPTED TO RECEIVE AN EMERGENCY SUPPLY OF COOLANT, THE TUBING BEING ARRANGED TO BE ELECTRICALLY HEATED IN ORDER TO HEAT THE CONTENTS THEREOF TO PROVIDE REACTION BETWEEN ELUENT AND REAGENT THEREIN.

Ap 3. E. L. DU RUM ETAL' 3,806,321

FLUID SAMPLE ANALYSIS SYSTEM 2 Sheets-Shebt 1 Filed Sept. 2, 1971 TIE 1RME W M W M XA 4 E ETSLM N V E /M WE m T MRRT A N M MH E ECPK

April 23, 1914 .L.DuRUM-m1. 3,39 ,321

FLUID SAMPLE ANALYSIS SYSTEM Filed Sept. 2, 1971 2 snms snet 2,

IE'IEL E.

r 7 T1 A 58 e 63 TI|3 :3 5O A A E L. a Q r l 6 l E V INVENTORSEMMETT'LDURRUM CHARLES O. FORGE PATRICK L.Y. LEE

KENT L. MACKINNON BY A fir? W ATTORNEYS US. Cl. 223-253 R 15 ClaimsABSTRACT OF THE DISCLOSURE A system 'for analyzing the constituents ofliquid Sample of a type wherein butters or other sample carrier liquidare applied to the sample characterized by an ion exchange column havinginput and output flow passages for passing the sample and buiferstherethrough together with means for supplying sample and buffer to theinput flow passage of the column under substantial positive pressure.The column contains ion exchange material for separating the sampleconstituents on a time basis. A reagent supply line under substantialpositive pressure discharges reagent into the eluent of the ion exchangecolumn for mixing reagent and eluent. Further, means in the reagentsupply line provide a back pressure resistance to passage of fluidtherethrough substantially matched to the back pressure resistanceprovided by the ion exchange column.

This system is further characterized by means for mixing the eluent andreagent in a manner which serves to intermingle reagent and eluent bylateral deflections of their travel along their flow paths whileinhibiting axial extension of portions of the body of mixed materialtraveling along the flow path so as not to upset the timed relation ofthe different successive constituents of sample (separated out of theion exchange column at different times). In addition, the system isfurther characterized by a reaction coil in the form of a length oftubing disposed in heat transfer relation about a support elementadapted to receive an emergency supply of coolant, the tubing beingarranged to be electrically heated in order to heat the contents thereofto provide reaction between eluent and reagent therein.

BACKGROUND OF THE INVENTION This invention pertains to a fluid sampleanalysis system for analyzing the constituents of a liquid sample of atype wherein bulfers or other sample carrier liquids are applied to theliquid sample and a proportionate amount of reagent is mixed with thebuffered sample whereby suitable means, such as an electrophotometerdevice using principles of chromatography can provide indicationsidentifying the constituents of the liquid sample. The system isparticularly useful in separating the components of a mixed amino acidsample using a cation exchange resin by sequential elution.

Heretofore, the separation of the constituents or components of a mixedamino acid sample has been accomplished by feeding the sample to acolumn of ion exchange resin composed of materials, such as a fixedmatrix of divinyl benzene cross-linked polystyrene or the like, to whichis attached a negative functional group, commonly sulphonic acid. Thesample is typically puddled on top of the resin column and thenbufliered sequentially by a number of buffering solutions or othersample carrier liquids. The sulphonic group of resin attracts thepositively charged amino acids, each of which has a characteristicafiinity thereto. Thereafter, the individual amino acid components aresequentially eluted from the ion exchange column and thereby appear ininverse order to the degree of resin atfinity for each component. Theeluent United States Patent O is then typically reacted with ninhydrinreagent to form a compound which absorbs light in a predetermined wavelength region. A prior system is arranged to direct the mixture througha flow cell past a colorimeter detector (for example, a photocell)which, when used with selected optical filters, is quantitativelyresponsive to that particular wave length.

The colorimeter detector or other electrophotometer is connected to arecorder which plots the response on a suitable medium, as on a chart.Quantitation is performed by time integrating each peak of the chart,each peak having a characteristic position and configuration dependentupon the amino acid type thereof.

The foregoing technique has characteristically required an excessiveamount of time, for example, on the order of several hours for proteinhydrolyzates, and even longer for physiological fluids.

Thus, there has been a need for a system wherein the constituents of thesample can be separated at a much faster rate without sacrifice ofreliability.

SUMMARY OF THE INVENTION AND OBJECTS In general, a system for analyzingthe constituents of a liquid sample wherein buffers or other samplecarrier liquids are applied to the sample has been provided to includean ion exchange column having input and output flow passages for passinga sample and buffers therethrough. The column contains a flow impedingmaterial serving to provide, at the input flow passage, a substantialback pressure resistance to fluid. flow therethrough. In addition, meansfor supplying sample and butter to the input flow passage undersubstantial positive pressure serves to feed buttered sample through thecolumn. A reagent is supplied to the eluent of the column via a reagentsupply line also under substantial positive pressure. The reagent supplyline includes means for providing a back pressure resistance to fluidflow therethrough in a manner to be substantially matched to the backpressure resistance to fluid flow through the ion exchange column asmeasured at its input end.

Since fluid compressibility and fluid viscosity can each be widelydifferent between the two subsystems which respectively include thereagent and ion exchange columns, the term matched is used above andherein in the sense that back pressure resistance of the reagent flow isestablished such that, at a given piston velocity of rod 37 (see below)the product of volume compressibility factor times back pressure ismaintained approximately equal for both the reagent and buffer paths.

Finally, means for mixing the reagent and eluent for analysis furtherdownstream in the system have been provided.

Preferably, the means for mixing reagent and eluent comprises a meansforming a flow path to receive both the reagent and eluent and means inthe flow path for intermingling reagent and eluent by lateraldeflections of their travel along the flow path while simultaneouslyinhibiting axial extension of portions of the body of mixed materialtraveling along the flow path. In addition, in supplying the sample andbuffers to the ion exchange column and reagent to its supply line undersubstantial positive pressure a positive displacement means suppliesbuffer and sample to the ion exchange column and reagent to its supplyline in a fixed ratio by volumetric flow rate while applying substantialpositive pressure to the column and impeded reagent path, the backpressure resistance to fluid flow through both the supply line and theion exchange column remaining substantially matched as noted above.

In addition to the above, and according to the invention, the systemfurther includes a reaction coil for receiving both the reagent andeluent of the ion exchange column in a manner whereby they will be mixedwith considerable lateral interaction and intermingling while axialextension of the body of mixed material will be inhibited. In thismanner, short blocks of mixed material will travel through the systemone after another in isolation of each other so as to be positivelyidentified by the electrophotometer means located in the flow path. Inaddition, as each block of mixed material passes through the reactioncoil provided herein, ,the mixed material will be thoroughly andeffectively heated due to the lateral deflection of the material whilemeans have also been provided for immediately quenching an overheatedblock of mixed material in the event of power failure, blockage of flowof material in the system, or other conditions which could cause thematerial to be heated for too long a period in the reaction coil asmight cause polymerization of the mixed material.

In general, it is an object of the present invention to provide animproved system for analyzing constituents of a liquid sample andparticularly to provide such a system in which a great number of fluidsamples can be analyzed over a relatively short period of time.

Another object of the invention is to provide an improved means forhandling a series of buffered sample portions in succession free ofaxial mixing therebetween so as to promote a block flow of each bufferedsample portion through the system.

Another object of the invention is to provide an improved reaction coilof a type wherein each block of buttered sample is heated by novelheating means and free of danger of overheating for prolonged periods.

The foregoing and other objects of the invention will become morereadily evident from the following detailed description of a preferredembodiment.

BRIEF DESCRIPTION OF THE DRAWING FIG. *1 discloses, in diagrammaticform, a system according to the invention;

FIG. 2 constitutes an enlarged showing of the valving conventionsemployed in the diagram in FIG. 1 for purposes of explanation;

FIG. 3 shows a transverse section view of four syringe componentsemployed in the system of FIG. 1 and figuratively taken along the, line3-3 of FIG. 1 for showing proportional diameters of the syringepl-ungers thereof;

FIG. 4 is a perspective view showing an ion exchange column of a type asemployed in the system of FIG. 1 and also of a type suitable forutilization as a reagent column employed in the system of FIG. 1;

FIG. 5 is a perspective exploded view showing a reaction coil taken fromthe system of FIG. 1; and

FIG. 6 is a transverse section view taken along the line 6-6 of FIG. 5.

DESCRIPTION OF A PREFERRED EMBODIMENT A system 10 for analyzing theconstituents of a liquid sample of a type wherein buffers or othersample carrier liquids are applied to a liquid sample is shown inFIG. 1.A sample holding unit 11, such as a previously loaded vial open at eachend and carried between fittings 12 at its ends, serves to dispose theliquid sample in a position whereby it can be injected into an ionexchange column 13. Preferably, the unit 11 includes inert previouslypacked material, such as boro-slicate glass beads of the order of 22 to40 microns diameter, for providing flow resistance believed to promoteblock flow as described below.

' Ion exchange column 13 basically consists of a length of very smalltubing 14 having an internal daimeter, for example on the order of 0.007inch. Tubing 14 is packed with a suitable ion exchange resin of a typeas used presently in the art.

The tubing column 14 is disposed within an isothermal metallic block'16having a readily heat transmissive characteristic, such as aluminum.Block 16 includes a slot 17 for receiving tubing 14 as well as a boredhole 18 extending a substantial distance along block 16 for receiving athermister probe 19 whereby a thermister bead 21 can be disposed deeplyinto block 16 as shown by the phantom line position 22. In this manner,the temperature at that point in block 16 can be readily detectedelectronically.

Means for heating block 16 includes the electric heater blanket 23 whichis held in its wrapped position by means of a pair of elastic rings 24.Conductive leads 26 may be used to connect an appropriate power supplyfor properly heating the isothermal block 16. The temperature of block16 is readily transferred to tubing 14 by means of a heat conductivepaste (not shown) of conventional type applied to the exterior of tubing14. Ion exchange column 13, accordingly, is considered to include inputand output flow passages 27, 28 at its upper and lower ends respectively(FIG. 1) for receiving and eluting liquid material.

A supply 29 of chemicals, such as buffers, distilled water, or reagents,.such as ninhydrin, etc., are maintained in reservoirs (not shown) to becoupled to the system by lines 31 vand suitable bubble traps 32, wherebya source of chemicals may be provided for the system operation asdescribed further below.

Means are provided for withdrawing fluid from the chemical supply andfor discharging same under substantial pressure, on the order of 2,000to 3,000 p.s.i., to the input flow passage 27 of ion exchange column 13and to supply a reagent, such as ninhydrin, along a supply line 33 to aninhydrin column 34 (of a construction corresponding to that shown inFIG. 4 for ion exchange column 13). Both columns 13 and 34 are arrangedto retain their previously packed material therein by suitable means,such as a five micron mesh stainless steel screen disposed at the bottomand top of the column so that each resin.- filled column can be handledas a unit prior to assembly in the system without loss of its resin.

In lieu of resin, column 34 can employ other suitable inert perviousmaterial, such as fine glass beads, of comparable size to provide thedesired flow impedance.

The means for supplying the chemical liquids to the two columns 13, 34in predetermined proportionate amounts includes a double actinghydraulic actuator 36 equipped with a piston rod 37 attached at itsouter end to a drive plate .38 of suitable rigid material, such assteel. The hydraulic control system 39 serves to move drive. plate 38between advanced and retracted positions to the right and left as shownin FIG. 1.

Drive plate 38 is further attached to the plunger elements 41-48disposed in opposed relation in pairs and distributed uniformly aroundplate 38 as shown best in FIG. 3. However, for schematic purposes, thesyringes 49-56 in FIG. 1 are arranged as shown for ease in explanationof operation of the system. Each plunger element moves in and out of arelated cylinder in the manner of a syringe 49-56. Accordingly, as bestshown in FIG. 3, it will be readily evident that the liquid displaced bythe plunger elements in syringes 52, 56 will be somewhat less than theliquid displaced by the other syringe elements.

It is intended that the various syringe elements, depending upon thechemicals with which they are to be used, shall be of a selecteddisplacement so as to supply a predetermined proportionate amount ofliquid in a fixed ratio with respect to the liquid which is supplied bythe other syringes. I v

The three schematic conventions used in FIG. l to show the valveactivity for valves employed-in the system is best explained withrespect to the three examples, shown in FIG. 2. In FIG. 1 all valves arede-energized.

Accordingly, in FIG. 2, the left hand valve element 57 is shown in aposition as would be represented when its associated solenoid 58controlling same is in its de-energized state. A spring 59 is shown formoving valve element 57 to its de-energized position so as to block feedline 62.

Accordingly, when solenoid 58 has been energized, valve element 57 isdrawn into a position so as to align its port, represented by the arrow61, with a feed line 62. Upon de-energizing solenoid 58, spring 59serves to move valve element 57 so as to interrupt the fluid path alongline 62.

Having in mind the foregoing explanation of the left hand valve unitshown in FIG. 2, it should be readily evident that in the center valveunit of FIG. 2 a pair of supply lines 63, 64 can be arranged to carryfluid in the direction shown by the arrows 66. Upon energizing solenoid67, the lower portion of the valve control unit 68 will move into theposition previously occupied by the upper end of unit 68 so as to form across-over connection between the lines 63, 64.

The right hand example shown in FIG. 2 represents a valve element 69operated by a solenoid 71 shown in its de-energized state. In thatcondition, the upper portion of the diagrammatic valve element 69 servesto form a fluid connection continuing line 72 while blocking ofl furtherpassage of fluid in a line 73. On the other hand, energizing solenoid71, serves to move valve element 69 upwardly against the force of spring74 whereby a fluid connection is made from the left hand side of 72a ofline 72 via the port represented by arrow 76 to connect 72a with line73.

For convenience in illustration the movement of the valve elementsdescribed in regard to FIG. 2 is shown as moving vertically whereas inFIG. 1 some valve elements move vertically and others horizontally.Thus, it is to be understood that the elements are merely shown to movebetween advanced and retracted positions.

Means are provided for receiving the eluent from ion exchange column 13and the discharge from ninhydrin column 34 for mixing these two bodiesof liquid and reacting them by passage through a reaction coil assembly77. The output from reaction coil assembly 77 is then fed to anelectrophotometer or colorimeter device 78 of suitable construction foroptically identifying the constituents of each successive block or bodyof mixed ma terial eluted from coil assembly 77.

Finally, a back pressure relief valve 79 is disposed immediatelydownstream of a back pressure gauge 81 for establishing a desired degreeof back pressure in the system suflicient to keep any bubbles insolution in the material in flow path 114 and coil 116. A collectionvessel 83 serves to collect the overflow material passing through thesystem.

Suitable means, such as manually operated switches (not shown), of aconventional nature have been provided whereby each of the valves 84-93may be operated to carry out the steps in various amino acid analysisruns or other analyzing runs on given liquid samples.

For example, if it is assumed that the hydraulic control system 39serves to operate actuator 36 to drive piston rod 3 7 leftwardly asshown in FIG. 1, fluid material in each of the right hand four lines 31leading from the chemical supply will be drawn into syrings 53-56 byvirtue of the condition of the valves 88-91 positioned as shown. Then,during the reverse stroke, selected ones of valves 88-91 can be shiftedunder a suitable control program whereby the fluid material fromsyringes 53-56 will be discharged either to column 13 or 34 or (wherevalves 88-91 have not been shifted) cycled back to supply 29.

Thus, the discharge of syrings 53-56 occurs under movement of plate 3 8and piston rod 37 to the right as shown in FIG. 1. At such time, it isto be understood that suitable known means serves to provide theprogramming and conditioning of valves 8 8-91 to their desired state sothat only those chemicals which are desired to be discharged move either(via valve 88) to the reagent supply line 33 (via line 102, check valve98 and a fluid manifold element M) or (via valves 89-91) to the ionexchange column 13 via manifold 108.

Syringes 49-52 function in the same manner as described above relativeto syringes 53-56 for both loading of chemical material and dischargethereof.

Assuming for the moment that the liquid in syringe 53 constitutes thefirst buffer to be applied to a liquid sample contained in sampleholding unit 11. valve 91 will be conditioned leftwardly so as totransfer the material discharging from syringe 53 via line 106, line105, check valve 101, line 107, buffer manifold 108, and subsequentlyvia line 109 to valve element 92. In the event that the solenoid (notshown) associated with valve 92 is energized (see FIG. 2), the controlelement 68 (FIG. 2) will be disposed in a position whereby the buttermaterial will be discharged along the line 112, via fitting 12 to sampleholding unit 11 where the liquid sample contained in unit 11 will beurged outwardly and upwardly along line 111 and transfer into input line27 leading to ion exchange column 13.

Assuming that one of valves 88-91 has been energized to feed liquid tocolumn 13 or 34, during the rightward advance of the drive plate 38, theliquid in the column will be under substantial pressure on the order,for example, of 2,000 to 3,000 psi. and each of valves 88-91 may bevariously operated in order to dispense predeterminel amounts ofchemical to be successively applied to the sample now moved to the topof ion exchange column 13 by the above described operation of valve 91.Pressure is relieved, however, whenever valves 88-91 are operated so asto simply return the chemicals to their source 29, i.e., recirculatedbetween syringe and source.

The perviously packed resin material in ion exchange column 13 causes aflow impedance generating a substantial back pressure resistance tofluid flow through that particular column. It is readily evident thatthe longer the column extends, the greater will be the back pressureresistance to liquid flow therethrough.

It has been observed that a high degree of reliability and repeatabilitycan be achieved in the results from a system of the above type byintroducing a means in the reagent supply line 3 3 for providing a backpressure resistance to fluid flow therethrough substantially matched toor at a selected optimum relation with the back pressure resistanceencountered at the input 27 of ion exchange column 13. In the presentinstance, a ninhydrin column of the type disclosed above is provided andpacked with a flow impeding material which is substantially inert to theliquid employed in the system, for example, resins of the type typicallyemployed in ion exchange columns. An objective in providing aflow-impeding ninhydrin column in addition to the ion exchange column inthe system is to provide a suitable means for developing a back pressureresistance to fluid flow which is proportional to the applied volumetricflow rate. It is has been observed that an extended column packed withpervious material serves to inhibit fluid flow in such a manner, and theimpedance of the flow through the ninhydrin column can be readilymatched to that of the ion exchange column. Thus, the ninhydrin column34 provides a means forming an iInpeded path for injecting a reagentinto the flow path defined by line 114 while the hydraulic actuator andsyringe arrangement provides a positive displacement means for supplyingbuffer and sample to the ion exchange column as well as reagent to theimpeded path thus formed. The optimum flow impedance can be closelyadjusted by employing the heater blanket 23 so as to vary the viscosityof fluid in column 34.

The fixed ratio of diameters of plunger elements 41-48 for the syringesshown clearly establishes a fixed ratio by volumetric flow rate for thesupplying of the various liquids into the system. At the same time, avery substantial positive pressure is applied to the column. Means formixing the eluent from column 13 and reagent from column 34 includes theT-connection 113 and flow path line 114 for receiving both the reagentand eluent. Means have been provided in the flow path 114 forintermingling reagent and eluent by laterally deflecting their travelalong flow path 114 while inhibiting axial extension of portions of eachbody or block of mixed material traveling along the flow path.

Flow path 114 further includes a spirally wrapped coil 116 having aninternal diameter of the order of 0.030 inch and containing a perviouslypacked inert material,

such as glass beads, having diameters in the range of between 0.007 to0.019 inch, i.e., somewhat larger than in the sample holding unit 11,since their function in coil 116 is intended to permit mixing of fluid.

As best shown in FIG. 6, the cross section of coil 116 discloses smallbeads 117 of suitable inert material, such as glass contained within atubing 118 of suitable inert material, such as tetrafluoroethylene resinas sold under the trademark Teflon, enclosed within a covering or sheath119 of stainless steel having a heating resistance on the order ofconventional heater wire elements.

A generally non-conductive but readily heat transmissive annular supportelement 121, such as an anodized aluminum cup, is formed with a helicalgroove 122 into which coil 116 is laid.

As noted above, the outer conductive covering 119 of coil 116 ischaracterized by a sutficient coefficient of electrical resistance so asto provide heating of fluid material within the tubing when electricallyenergized as by means of the variable power supply 123 connected tosheath 119 by means of lead 124 while both ends of coil 116 are groundedas, for example, at leads 125, 126. Lead 124 contacts sheath 119substantially midway between its ground points 125, 126 so as to providetwo parallel equally heated branches to the circuit branching from themid-point along the length of sheath 119.

Means are provided for directly sensing the temperature of the coveringor sheath 119 so as to adjust power supply 123 to vary the heating ofthe tubing in response to changes in the temperature of the sheath 119.Accordingly, a thermister probe 127 carries a thermister bead 128 intodirect engagement with the outer surface of sheath 119 so as toimmediately sense any change in temperature effected thereat by means ofpower supply 123.

In this way, oscillations in the power supply are held to aninconsequential minimum since the sensing of a change in heating of thetubing is virtually instantaneous with respect to the application ofincreased power applied to the circuit. Feedback to the variable powersupply 123 is supplied by a lead 129. Variable power supplies ofconventional and known construction are readily adaptable to control bythe output of changes in resistance occasioned by temperature changes asaffect thermister beads in the manner shown and, accordingly, detaileddsecription of such control circuitry is not believed required for thoseskilled in the art.

The provision of a previously packed coil of beads as described aboveserves to promote what has been referred to as block flow of discretebodies of eluent and reagent so that they may be mixed thoroughlywithout axial extension of their end portions as would otherwise cause aloss in discrimination in the detection and identification of suchmaterials by the electrophotometer 78. It has further been observedherein that such bloc-k flow is promoted by the provision of glass beadsor other previously packed inert material in coil 116 to cause the bodyof mixed material to be deflected laterally-of its path by tumbling theliquid material in and around the glass beads obstructing the path andin this manner causes the body of mixed material to engage the heatedside wall of coil 116 to a greater degree than would otherwise beachieved. In this manner, a more uniformly heated mixture has beenobserved to be obtained than heretofore, and it is believed that in thisway improved discrimination among the constituentsmay be obtained by thedisclosed system.

Further, by locating the electrical heating means immediately adjacenttubing 118, it will be readily evident that immediate heating responseis obtained and permits the use of a feedback temperature-detectingsystem of the kind disclosed.

Finally, means have been provided for quickly quenching the heat of themixed materials disposed in coil 116 in the event that they shouldremain in the coil too long as, for example, by means of a power failureor other flow blockage condition which might, through prolonged heating,cause the polymerization of the mixed materials. Thus, the centralportion of support element 121 forms a hollow receptacle 131 formedwithin the support element for admitting liquid upwardly therein via aninlet port 132. Coil 116 is disposed in heat transfer relation withrespect to the walls of receptacle 131. A liquid reservoir 133 is filledpartially (up to water line by passing water or other coolant, intoreceptacle 131 for draining downwardly via ports 132, 136. An airpressure inlet 134 and air pressure line 137 serve to force the coolantupwardly as now to be described.

A flow passage formed by means of the tubing or pipe 138 is coupled tothe inlet port 132 and disposed and adapted to originate at one end 139'at a point substantially beneath the surface level 140 of the coolingliquid in the reservoir. Outlet 136 supplies the cooling liquid fromreservoir 133 to receptacle 131 via inlet port 132. A source of gas,such as compressed air, under pressure, is continuously stored in thetank 141 (FIG. 1) and coupled via a reducing valve 142 so as to directpressure into the upper part of reservoir 133 for forcing the coolingliquid into receptacle 131.

The pressure is applied to reservoir 133 only under certain conditionsas, for example, where there is a power failure and, accordingly, asolenoid 143 is arranged to operate the spool within valve 93 betweeneach of two conditions. The condition of solenoid 143 during normaloperation of the system is to be energized and to hold the spool ofvalve 93 downwardly against spring pressure so as to vent supply line137 to atmosphere via passage 144. On the other hand, when there is apower failure or other operative condition which serves to deenergizespring to its upward position so as to interconnect supply solenoid 143,the spool in valve 93 is driven by the valve line 137 with the gaspressure line 145 thereby causing a portion of the liquid in reservoir133 to be forced upwardly into receptacle 131, lowering the liquid levelto line 151.

Thus, therehas been provided means for interconnecting the pressuresource to the reservoir so as to displace liquid therefrom into thereceptacle to dispose a cooling liquid into heat transfer relation withthe heat transmissive walls of support element 121 for cooling same andalso for cooling the coil 116 disposed in heat transfer relation to theouter side wall of element 121.

It is to be observed that the lower end 139 of tubing or pipe 138 isspaced somewhat clear of the bottom of reservoir 133 so as to divide theliquid therein into a first and second portion, one portion being abovethe end 139 and the other portion being below end 139. In this manner,the pressure applied to liquid in reservoir 133 serves to feed apredetermined volume of liquid upwardly into receptacle 131 whileretaining a reserve of relatively cool liquid in reservoir 133.Subsequently, when valve 93 is conditioned to vent reservoir 133 toatomsphere, the warmer liquid within receptacle 131 will returndownwardly into the relatively cool liquid reserve in the bottom ofreservoir 133 and thereby be quickly cooled. In this manner, in theevent that a second emergency should occur relatively closely followingthe first, it can be assured that there will be an adequate supply ofthoroughly cooled liquid in reservoir 133 so as to permit a secondoperation of the quenching system.

Finally, means forming a closed overflow chamber 146 and a fluid flowpath in the form of the tubing 147 extending upwardly from the topclosure 148 of receptacle 131 forms'an adequate storage for thesuccessive flooding of receptacle 131 by a relatively larger volumereservoir 133 than shown. As cooling liquid is forced upwardly throughreceptacle 131, it will over-flow upwardly into chamber 146. As chamber146 fills, air or other gas trapped within chamber 146 will becomecompressed. Ultimately, upon venting valve 93 to atmosphere, it will bereadily evident that the compressed gas contained in chamber 146 servesto quickly purge chamber 146 and receptacle 131 of cooling liquid tosend it quickly returning into reservoir 133.

From the foregoing, it will be readily evident that there has beenprovided a novel system and apparatus for running a series of analysesof fluid samples with highly improved repeatable results anddiscrimination.

It will also be readily evident that the length and type of previouslypacked material contained within the reagent to supply line 33 can serveto provide a substantially matched or optimum relationship between thepressure on the reagent supply line 33 as measured by gauge 149 and thepressure detected by gauge 150 indicative of the pressure at input 27 onthe ion exchange column 13.

Discrete identification of each eluent derived from a common sample isobviously maintained by means of the discrete block flow handlingeffected by utilization of the lateral deflection of the materials ineach discrete body of mixed liquid traveling along the path 114 as bymeans of the glass beads located within reaction coil 116. In this way,axial merging of successive blocks of mixed eluent is precluded wherebythe electrophotometer means 78 can readily discriminate betweensuccessive ingredients being examined.

Finally, manual manipulation of switches can readily serve to controlthe various valve units shown in the diagram in FIG. 1 so as to carryout any selected sequence of operations.

In addition, by means of the hydraulic drive operating a plurality ofsyringes in the manner shown, it is possible to provide reliable fixedfeeding ratios as between the various chemicals required to be injectedinto the system. Thus, it is believed that this portion of the systemalso contributes substantially to the enhanced results obtained.

We claim:

1. In a system for analyzing the constituents of a liquid sample of atype wherein buffers or other sample carrier liquids are applied to thesample, an ion exchange column having input and output flow passages forpassing said sample and buifers therethrough, means for supplying sampleand buffer to said input flow passage under substantial positivepressure, said column containing an ion exchange material, means forsupplying a reagent to the eluent of said column, the last named meansincluding a reagent supply line, and means in said reagent supply linefor providing a substantial positive back pressure resistance to fluidflow therethrough substantially matched to the back pressure resistanceprovided by said ion exchange column and means for mixing said reagentand eluent for analysis downstream.

2. A system for analyzing the constituents of a liquid sample accordingto claim 1 in which said means in said reagent supply line comprisesmeans for developing a back pressure resistance to fluid flowproportional to applied volumetric fiow rate.

3. A system for analyzing the constituents of a liquid sample accordingto claim 2 in which the last named means comprises a column ofperviously packed material serving to inhibit fluid flow therethrough,the impedance thereof substantially matching that of said ion exchangecolumn.

4. A system for analyzing the constituents of a liquid sample accordingto claim 1 further including means for providing a positive fixed ratioby volumetric flow 10 rate of the buffer and reagent as they aresupplied while simultaneously applying substantial pressure to each.

5. In a system for analyzing the constituents of a liquid sample of atype wherein buffer-s or other sample carrier liquids are applied to thesample, an ion exchange column having input and output flow passages forpassing said sample and buffers therethrough to be discharged along aflow path for analysis downstream, means forming a reagent column havinginput and output flow passages for passing reagent therethrough, areagent supply line coupled to supply reagent to the last named saidinput, means in said reagent supply line for providing a substantialback pressure substantially matched to that of the exchange column, thelast named output fiow passage serving to inject reagent into said flowpath, and positive displacement means for supplying. butter and sampleto said ion exchange column and reagent to said reagent column in afixed ratio by volumetric flow rate while applying substantial positivepressure to said column and impeded path.

6. A system for analyzing the constituents of a liquid sample accordingto claim 1 wherein the last named said means for mixing includes meansforming a flow path to receive both said reagent and stationary eluent,and means in the flow path for intermingling reagent and eluent bylateral deflections of their travel along said flow path whileinhibiting axial extension of portions of the body of mixed materialtraveling along said flow path.

7. In a system for analyzing the constituents of a liquid sample of atype wherein buffers or other sample carrier liquids are applied to thesample and a reagent is mixed with the buifered sample, an ion exchangecolumn discharging an eluent of a bulfered sample, a reagent supplyline, means in said reagent supply line for providing a substantial backpressure substantially matched to that of the exchange column, and meansfor mixing reagent and said eluent, the last named means forming a flowpath for receiving said eluent and reagent and stationary means in theflow path impeding the flow of and serving to intermingle reagent andeluent by lateral deflections of their travel along said flow path whileinhibiting axial extension of portions of the body of mixed materialtraveling along said flow path.

8. A system for analyzing the constituents of a liquid sample accordingto claim 7 wherein the last named said means for mixing includes alength of tubing forming a flow path to receive both said reagent andeluent, inert beads filling a portion of said flow path for laterallydefleeting reagent and eluent to mix these materials in their travelalong said flow path while inhibiting axial extension of the endportions of the body of mixed materials traveling in said tubing.

9. A system for analyzing the constituents of a liquid sample accordingto claim 8 further including a generally non-conductive but readily heattransmissive annular support element, said length of tubing including anouter conductive covering of material having a sutlicient coefficient ofelectrical resistance to provide heating of fluid material withinsaidtubing when electrically energized, said tubing being disposed andcarried by said support element, power supply means electrically coupledto said covering for heating same and said fluid material within saidtubing, and means directly sensing the temperature of said covering foradjusting said power supply means to vary the heating of said coveringin response to changes in the temperature of said covering; 1

10. A system according to claim 9 wherein said tubing is wrapped as acoil about said support element in heat transfer relation thereto.

11. In a system for analyzing the constituents of a liquid sample of atype wherein a buttered sample is mixed with a reagent before flowing toan analyzing station, means for mixing said reagent and buffered samplecomprising a length of tubing forming a flow path to receive both saidreagent and buffered sample, said tubing including glass beads thereinfor laterally deflecting reagent and buflered sample to mix thesematerials in their travel along the tubing while inhibiting axialextensionof the end portions of the body of mixed materials traveling inthe tubing, a generally non-conductive but readily heat transmissiveannular support element, said length of tubing being carried by saidsupport element, electrical conductor means adjacent said tubing andwrapped about said element, said electrical conductor means having asuflicient coefiicient of electrical resistance to provide heating offluid material within said tubing when electrically energized, powersupply means electrically coupled to said conductor means for heatingsame and said fluid material within said tubing, and means directlysensing the temperature of said conductor means for adjusting said powersupply means to vary the heating of said conductor means in response tochanges in the temperature thereof.

12. In a system for analyzing the constituents of a liquid sample of atype wherein a buttered sample is mixed with a reagent before flowing toan analyzing station, means for mixing said reagent and buffered samplecomprising a length of tubing forming a flow path to receive both saidreagent and buffered sample, said tubing including glass beads thereinfor laterally deflecting r-eagent and buffered sample to mix thesematerials in their travel along the tubing while inhibiting axialextension of the end portions of the body of mixed materials travelingin the tubing, a generally non-conductive but readily heat transmissiveannular support element, said length of tubing being carried by saidsupport element, electrical conductor means adjacent said tubing andwrapped about said element, said electrical conductor means having asufficient coeflicient of electrical resistance to provide heating offluid material within said tubing when electrically energized, powersupply means electrically coupled to said conductor means for heatingsame and said fluid material within said tubing, means directly sensingthe temperature of said conductor means for adjusting said power supplymeans to vary the heating of said conductor means in response to changesin the temperature thereof, means for quickly quenching the heat of themixed body of materials in said tubing comprising a hollow receptacleformed within said support element for receiving liquid therein, saidcoil being disposed in heat transfer relation with respect to the wallsof said receptacle, a liquid inlet port formed in said receptacle, aliquid reservoir having an inlet and outlet, a flow passage coupled tosaid inlet port of the receptacle and disposed and adapted to originateat one end at a point substantially beneath the surface level of liquidin said reservoir, the outlet of said reservoir being coupled to supplycooling liquid from said reservoir to said receptacle via its saidliquid inlet port, a source of gas under pressure coupled to lead intosaid reservoir for forcing the liquid therein into said receptacle, andmeans for interconnecting said pressure source to said reservoir todisplace the liquid therefrom into said receptacle thereby tobring acooling liquid into heat transfer relation with the heat transmissivewalls of said support element for cooling same and said coil.

13. In a system for mixing a buffered sample with a reagent whileheating the mixed body of liquid, the combination comprising a hollowreceptacle forming an annular support body, the material of the walls ofsaid body being readily heat transmissive, a length of tubing forreceiving said buffered sample and reagent and wrapped as a coil in heattransfer relation to said support body, means for heating the liquidbody of material within said tubing, and means for quickly quenching theheated material including a liquid reservoir havingan inlet and outlet,a liquid inlet port formed in said receptacle and coupled to a flowpassage disposed and adapted to originate at one end at a pointsubstantially beneath the surface level of liquid in said reservoir, thereservoir outlet being coupled to supply cooling liquid from saidreservoir to said receptacle via its said liquid inlet port, a source ofgas under pressure coupled to lead into said reservoir for forcing theliquid therein into said receptacle, and means for interconnecting saidpressure source to said reservoir to displace the liquid therefrom tosaid receptacle thereby to bring a cooling liquid into heat transferrelation with the heat transmissive walls of said support body elementfor cooling same and said coil.

14. A system for mixing buffered sample and reagent according to claim13 further comprising means disposing said one end of the first namedflow passage intermediate the level of liquid in said reservoir and thebottom of said reservoir to divide the liquid into a first portion abovesaid end and a second portion below said end, means forming an overflowchamber and a fluid flow path from said receptacle to said chamber, andmeans for displacing one of said portions into said receptacle uponoperation of said interconnecting means whereby to leave a substantialreserve portion of liquid in said reservoir for quickly coolingreturning liquid of said one portion.

15. A system according to claim 14 wherein said overflow chamber isformed as a closed chamber for containing a gas compressible upon entryof liquid into said chamber whereby said compressed gas within theoverflow chamber serves to more readily discharge liquid from within thechamber.

References Cited UNITED STATES PATENTS 3,334,969 8/1967 Catravas 23253 X3,375,080 3/1968 Fujii et al. 23253 3,458,285 7/1969 Hrdina 23253 X3,630,681 12/1971 Arikawa 23253 X 3,118,735 -1/1964 Favre et a1 23253 X3,374,064 3/1968 Kolsto' 23253 PC 3,497,322 2/1970 vBoys 23253 3,679,3647/1972 Teal et a1 23-253 PC MORRIS O. WOLK, Primary Examiner R. E.SERWIN, Assistant Examiner

